Thread-cutter operating mechanism for sewing machines



Sept. 8, 1931. E. B. ALLEN 1,822,639

THREAD CUTTER OPERATING MECHANISM FOR SEWING MACHINES Filed June 27,1950 5 Sheets-Sheet 1 il.. Sq

Sept. 8, 1931. E. B. ALLEN 1,822,639

THREAD CUTTER OPERATING MECHANISM FOR SEWING MACHINES Filed June 27,1930 5 Sheets-Sheet 2 gmmtoz Edlund Alle/z Muna.'

Sept. 8, 1931. E. B. ALLEN 1,822,539

THREAD CUTTER OPERATING MECHANISM FOR SEWING MACHINES Filed June 27,1930 5 Sheets-Sheet 5 gwoentoz Sept. 8, 1931. E. B. ALLEN 1,822,639

THREAD CUTTER OPERATING MEGHANISM FOR SEWING MACHINES Filed June 2'7,1930 5 Sheets-Sheet 4 Edward Alle I WE@ E. B. ALLEN Sept. 8, 1931.

THREAD CUTTER OPERATING MECHANISM FOR SEWING MACHINES 5 sheets-sheet 5Filed Jupe 27, y1930 Edd/afa ZZeM Patented Sept. 8, 1931 UNITED STATESPATENT OFFICE EDWARD B. ALLEN, OF NEWTOVVN, CONNECTICUT, SSIGNOR TO THEVSINGER MANU- FACTURING COMPANY, OF ELIZABETH,

JERSEY' NEW JERSEY, A CORPORATION OF NEW THREAD-CUTTER OPERATINGMECHANISM FOB SEWING MACHINES Application filed June 27,

This invention relates to sewing machines and more particul arly tosewing machines of the straight buttonholc type having a stopmotiondevice for controlling the period of operation ot the stitch-formingmechanism nd also having an upperthread nipper and cutter mounted on thework-clamping foot, as represented in the Allen Patent No. 885,- 310.

V-Vith a machine of this character, the stopmotion device must stop themachine with the upper-thread take-up at its highest point, so that,when the machine is again started, the upperor needle-thread will not bebroken or pulled out of the nipper and so that the first stitch will beproperly and 'fully tightcned. When the take-up is at its highest point,however, the needle has executed the first part of its down-stroke and,while it has not reached the path of the upper-thread-cutter, there isdanger that, as it dips further during` the overthrow motion or motionof compression of the usual stop-motion butterspring, its point mayreach the path of the thread-cutter and be blunted by interference withthis cutter which is customarily tripped into action by the rip-motionof the stopplunger into the notch ot the stop-cam immediately precedingthe overthrow motion or motion of compression of the usual bufferspring.In other words, in the machine referred to, the needle-thread cutter isexe` cut-ing its closing or thread-cutting and -nipping movementsimultaneously with the down movement ot' the needle permitted by theoverthrow or butler-compressing movement of the machine incident to theoperation of the stop-motion device. Hence the danger of interference bythe needle in dipping into tl e path ot the thread-cutter.

The present invention has for an object to eliminate the danger ofblunting the needle by interference with the upper-thread cutter.

`With the above and other objects in view, as will hereinafter appear,the invention consists in the devices, combinations and arrangements ofparts herein after set forth and illustrated in the accompanyingdrawings of a preferred form of the invention, from which the severalfeatures of the invention and the 1930. Serial No. 464,177.

advantages attained thereby will be readily understood by those skilledin the art.

In the accompanying drawings, Fig. l is a side elevation of a buttonholesewing machine embodying the invention. Fig.. 2 is a horizontal secionthrough the bracket arm standard .of the machine, showing the machine-bed in plan. Fig. 3 is a bottom plan view of a portion of themachine-bed. Fig. 4 is a transverse vertical section through the machinebed on the line 4 4, Fig. 2. Fig. is a rear end elevation of themachine. Fig 6 is a detail view of an element of Fig. 5. Fig. 7 is adisassembled perspective view of the stop-cam and buffer springmechanism of the stop-motion device. Fig. 8 is a view illustrating theupper thread-cutter tripping mechanism with the parts in theirrespective positions occupied as the stop-motion plunger enters thenotch in the stop-cam and before there is any overthrow orbuiier-compressing motion of the machine parts. Fig. 9 is a similar viewshowing the part-s in full lines at the end of the overthrow motion ofthe machine parts and, in dotted lines, the movement imparted to theneedle thread-cutter release mechanism by the recovery or return motionof the buffer mechanism, following the overthrow or buffer-compressingaction of the stop-motion mechanism. Fig. l() is a face view of theneedle-bar reciprocating and take-up actuating mechanism, and Fig. 1l,is a fragmentary top-plan view of the tension-release mechanism.

rThe machine illustrated comprises a bed 1, standard 2, overhangingbracket-arm 3 and head 4 in which is journaled the reciprocating andlaterally vibrating needle-bar 5 carrying the needle 6. The needle-bar 5is operated by the usual connections with the main-shaft 7. Cooperatingwith the needle 6 below the bed l is the usual oscillatory shuttle S,and the needle-thread loops are drawn up and tightened by means of theusual link take-up 9. As shown in Fig. l0., a take-up of this charactercomprises a bell-crank lever 9 which at its lower end embraces acrank-pin l() on the main-shaft 7 and is pivotally connected at 11 to ananchor-link 12. The take-up actuating crank-pin 10 commonly is angularlyoffset from and lags behind the needle-ber-operating` crank-pin 13, sothat when the take-up thread-eye 14E is at its highest point, Figs. 1und 10, the needle-bar 5 has executed the lirst part of its down-motion.

The machine comprises the usual Workclamp including the crossslide-plate 15 in which is mounted the longitudinal slide-plate 1Gcarrying; the tulcruni-support 17 for the upper clamp-lever 18 which atits foriva rd end carries thc clump-toot 19. During` the sewine'operation the Work-clamp is moved over the bed ll to place the stitchesin the desired order or arrangement around the luittonliole by the usualconnections (not shown) with the feed-caln-grooves 20 and 20, Fig. 1, inth e feed-wheel 2O which is 1steered to the inainshatt 'l' and inakesone complete revolution per buttonhole-producing cycle.

llflounted in the upper clamp-toot 19 on the short vertical shaft 21 arethe usual needlethreud cutter and nipr r blades 22 which are arranged tosweep horizontally across the needle-path or lead oi: the needle-threadat the close oit a sewing period to cut an d hold the needle-thread inthe manner disclosed in said lrllen Patent No. 885,810. The shaft 21carries a crank-erin 23 to which pvotally connected ay ber 24 slidablysupported neer its reni' end in the bracket 25 and cneroized by thespring; 25. Fig. 2, to close 1the tln'ead-cutter and -nipper blades.llfhen sewing); down the return side oit' the buttonhole. the rod 24which is moving' endvvise of itselic in rearward direction encountersthe usual latch-arm 27 and has its inotion arrested While the continuedrearward inotion ol the vvork-clan'ip opens the thread-cutter. lVhen theserving; is conuileted, the parts are in the po` ons shown in Fie'. 2and the thread-cutter 22 is held open bv the latch-arno 27 which istit-ted to the horizontally disposed rockshett 28 mounted at one side ofthe standard 2 and conunon to machines ot this type. Actnation ot therock-shaft 28 Will therefore serve to reise the laten-erin 2T to dottedline position, Fig. fl, and release the needle-thread cutter 22.

The rock-shaft 28 also has tired thereto the bent erin Figs. 1 and 4i,the forked front end which embraces the rearward end of the erin il()lived to the tension-release rockshalt 81 cerryino; the Wedge-pointedarin Fier. 1l., Vtor relcusinfthe dra@ of the tension-device 88 upon theneedle-thread. The Wedge-pointed arm 82 is arrene'ed close to thelimoen-disks 88 so thet. when the rocksbalzi: is operated, thetension-device Will be opened before the thread-cutter sind -ni nner 22is releesed, whereby slack needlethread is provided to be drown bv themovable cutter and nipper bled-es into Dipped position hetvreen suchmovable blades end the usuel stationary upper nipper member not shovni)`common to a thread-cutter and -uippcr ci this type, as shown in saidAllen utent No. 885,810.

lrlounted loosely on the rock-shaft 28 a bell-crank lever 84., 35, thearni of which entends dovmwardly through an aperture 36 in the bed 1sind is connected as usual to actuate the wider-thread cutter andpull-ott' operating); lever 3T, substantially as shown in said PatentNo. 885,810. The arn'i 85 of the bell-crank lever has an aperture at itsfree end tor connection with the usual pedal-operated clamp-liftingchain (not shown). There is also connected at 88 to the bell-crank leverarm 3 a vertical rod 39 which is guided at its lower end in the bracketLl() and carries the Work-clamp lifting" roller 1-1 disposed ahovc andadapted to depress the tail 18 of the upper Work-clamp lever 18 to raisethe clamp-'toot 19 for release of the Work. The vertical rod 89 has anotch ,l2 in one side :ulaixited to he entered by one end of thelockine' lever t8 the other end of which is formed with an upf-tendinglip lt in the path ol movement et the louer end ot a curved arm fixed tothe rock-shaft 28. Then the niachine is sewing', the lever -18 is in thenotch l2 ot the rod 80 und the bell-crank lever 34, 35 is locked aeainstmovement. by the operator. lt ie ruilocked by the saine rocking`inoveinent ot the shaft 28 which releases the needlethread-cutter undopens the tension-device.

The stop-motion device Ylor controlling; the period ot operation ot thestitch-l'oriningv mechanism is preferably constructed substantially inaccordance With the disclosui'e of' the Allen and Myers application,Serial No. 272,416. liled Apr. 24.1. 1928. The main-shaft i has fixed toit the `egear fl-G which drives the ,Q'ear if? et half speed. The shaftalso carries the usual tight and loose belt-pulleys 48.9..respect-ively. The /17 constitutes a housing; for the buffer-springs50, 51 disposed between the abutment 52 iXed Within and to the gear L17and the block 53 disposed within und relative to which the gear l? is.tree to move to a limited extent. The block is connected to the pin54.- on the stop-cani 55 loose on the bearing stud 55 on which the ,gearl? is journeled.

Cooperating' with the stop-cani 55 is the usuel verticallyspring-pressed plunger 56 mounted in the tilting stop-motion lever 57which includes the usual belt-shipper erin 58. The present stop-cani 55is of duplex construction, that is, it has tvvo diainctrically opposedstop-notches 59 and tivo plungerdepressing eccentric portions 60. Thestopniotion lever 57 is held in its tilted or runnine; position, Fie: 1,by the usual 'feed-canecontrolled latch-lever 51 Which enters a notch 5lin the side of' the vertically spring-pressed latch-rod 62 connected atits upper end to the arm 68 rinid with the stop-motion lever 57. Whenthe tripping1 point (S4 on the toedcani 20 trips the hitch G1, thestop-motion lever 57 will spring to its vertical or dotted lineposition, Fig. 1, in which positie-n `the-upper end ot' the plunger bar56 will be engaged by one of the eccentric portions 60 of the stop-cam55 and depressed, after which the plunger'- bar 56 will be projectedupwardly by its spring into the succeeding stop-notch 59 and arrestfurther movement of the cam 55.

The main-shaft 7 oi the machine and the parts connected thereto anddriven thereby have momentum at this time and, to avoid excessive shock,provision is made for an overthrow or momentum absorbing motion of themain-shaft and gear 47 after the stop-cam is locked in stopping positionby the stopmotion plunger 56. rhis overthrow motion oithe gear 47 causesthe abutment 52 to compress the butler-spring 51 against the thenstationary abutment-block Following the overthrow motion of the gear 47is a recovery motion of said gear in a reverse direction to the finalstopping position or position of rest of the main-shaft 7.

According to the present improvement, advantage is taken ot this reverseor recovery motion of the parts following the overthrow orbuffer-compressing motion ot' the mainshaft and connected parts to tripthe upper or needle-thread cutter, open the tension device, unlock thework-clamp or perform any desired operation auxiliary to the sewingoperation, t-he time of which auxiliary operation it may be desirable todelay as late as possible in a buttonhole producing cycle.

To this end a novel mechanism actuated by the recovery motion of thegear 47 is provided or imparting a rocking impulse to the sha tt 28which heretofore has customarily been rocked by the 11p-motion of theplunger bar 56 into the stop-notch of the usual stopcam. FiXed to therear end of the rock-shaft 28 is the arm 65 having pivoted thereto at 66a follower element comprising a lever 67 the upper end ot which isformed with a hoolishoulder 68 disposed in the plane of the actuato-rcam-plate 69 which is fixed by screws 79 passing through arcuate slots71 in the camplate 69 to the cover-plate 72 for the bufferspring` cavityin the gear' 47; the cover-plate 72 being screwed to the internal hub 73of the gear 47. The cam-plate 69, which is'thus a iiXed part of the.gear 47, is formed with diametrically opposed shoulders 74 with one orthe other oi which the hook-shoulder 68 cooperates on the recoverymotion of the gear 47 to rock the shaft 28.

The lever 67 which is normally urge-d toward the cam-plate 69 by thespring 75 is hel d in retracted or inactive position, out of engagementwith the cam-plate 69, Figs. 2 and 5, by the side pressure tlhereagainstot the head 76 of the pin 77 fixed to the tilting stop-motion lever 57.When the stop-motion lever 57 springs to vertical or stopping position,the head 76 of the pin 77 is carried out of engagement with the lever 67which is tree to be swung by its spring 75 into the -reduced neck 78 ofthel pin 77, whereby the upper end of the lever 67 is carried intoengagement with the edge of the cam-plate 69, as shown in Fig. 8.

The shoulders 74 are so timed on the gear 47 that when one of thestop-notches 59 of the stop-cam is engaged by the stop-motion plunger56, at which time the overthrow or builer-compressing motion of thepartsy begins, one of the stop-shoulders 74 will be near thehook-shoulder 68 on the lever 67, asshown in Fig. 8. At this time, thetake-up 9 is at its highest point and the needle 6 has executed theiirst part of its down-stroke and is moving downwardly under themomentum or buffer-compressing or overthrow-motion of the parts. J ustbefore this overthrow-motion is completed, the shoulder 74 is 'carriedpast the hook-shoulder 68 which latter moves inwardly or hooks over theshoulder 74, as shown in Fig. 9, which represents the parts at the endof trie overthrow motion or the beginning oi the reverse or recoverymotion, during the execution of which reco-very motion the needle of thesewing machine is moving upwardly or away from the path of theneedle-thread cutter and the arm 65 is being lifted to dotted lineposition and imparts the desired rocking impulse to the shaft 28.

lVhen the recovery motion is spent, the main-shaft 7 will have returnedto the same position it occupied when the stop-motion plunger 56 firstentered one of the stop-cam notches 59. The take-up will be at itshighest point. During the last part of the rocking` movement of theshaft 28, the latch 27 is raised out of engagement with the needlethreadcutter-control rod 24, thereby releasing said rod at a time when theneedle is moving upwardly or away from the needle-thread cutter and whenall danger of interference between the needle and thread-cutter is past.The line ,/z, F ig. 8, represents the position of the main-shaft whenthe take-up 9 is at its highest point and when the plunger 56 engagesthe stop-notch 59. The line b, Fig. 9 represents the position of themainshaft at the end of its overthrow motion and the line c representsthe position of the mainshaft at the end of its recovery motion; lines cand a. being in the same vertical position.

By virtue of the slots in the plate 69 lirough which the screws pass,said plate may be adjusted circular-ly relative to the gear 47 to insurethat one ot the shoulders 74 will be carried past the hook-shoulder 68at the end of the overthrow motion of such gear.

The tension-release arm 32 is timed to release thetension before thethread-cutter is trilbed,so that free needle-thread will ybe supplied tobe carried into the nipper assoliated with the thread-cutter.

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The work-clamp lock-lever 43 will also be moved te unlocking or dottedline position, Fig. 2, by the recovery motion of the mainshatt 7 andgear Ll?, so that the usual manually operated work-clamp-litting andunder threznl-cutter-operating lever 35 cannot be actuated while thereis danger' oi interference with the moving needle.

Means are preferably provided to insure the closing of the work-clampprior to startingl the machine. To this en-d there is cennected to alateral-arm 57 on the stop-motion lever 57'one end of a` link 79 theother end of which is Connected to a lever 8O fulcrumed at 8l on themachine-bed and having an angular arm 82 extending back of the leverarm84, F10'. 2, which is rigid with the manually operated clamp-lifting arm35. Vhen the stop-motion lever 57 is tilted to running or full lineposition, Fig. l, the link 79 pulls on the lever 80 'forcing its arm 82against the side et the lever-arm ed and forcing the lever upwardly tolower the work-clamp.

The cam-incline 78 between the neck 78 and head 7 6 of the pin 77 servesto retract the lever 67 from the cam-plate 69 when the stop-motion lever57 is shifted to running position. This motion releases the rock-shaft28 which thereupon moves to restore the tension on the thread and allowthe clamp-locking lever 43 to enter the notch 42 in the vertical rod 39.

lhile the invention is shown as embodied in a machine having thestop-motion mechanism of the Allen and Myers application, referred to, Ido not find it necessary to coniine the invention to that exactmechanism. The invention is obviously adaptable to any torni ofstop-motion mechanism, the oper tion of which involves a retrogrademotion of certain parts immediately preceding the inal stoppage of themachine.

Having thus set forth the nature of the invention, what I claim hereinis:

l. A sewing machine having stitch-forming n'iechanism, a main-shaft, astop-motion device including means for imparting aA retrograde motion tothe main-shaft betere bringing it to a iinal rest, a thread-cutter, andmeans actuated by fan-element of the machine in the retrograde motion etthe parts or operating said thread-cutter.

2. A sewing machine having stitch-forming mechanism, a main-shaft, astop-motion device including a resilient buffer for absorbing tlemomentum of the machine in bringing it to rest, a needle-thread cutter,and means actuated by an element of the machine in the recovery motionoli' the parts succeeding the butler-compressing motion for operatingsaid thread-cutter.

3. A sewing machine having stitch-forming mechanism including areciprocating needle, a main-shaft, a needle-thread tension device, aneedle-thread cutter and nipper, a

stop-motion device including a resilient bufiter for absorbing themomentum of the machine parts and imparting a reverse motion to saidparts before bringing the machine to a inal position of rest, and meansactuated by an element of the machine in the reverse motion of the partsfor lirst releasing the tension-device and then operating theneedlethread cutter and nipper.

4. A sewing machine having in combination, stitch-forming mechanismincluding a reciprocating needle, a work-clamp, a needlethread take-uptimed to be at its highest point after the needle has executed the firstpart of its down-stroke, a needle-thread. cutter mounted on saidwork-clamp to cross the path of the needle, a main-shaft, a stop-motiondevice inclnding means for imparting a retrograde motion to themain-shaft before bringing it to a linal rest with the take-up at itshighest point, and means actuated by an element et the machine in theretrograde motion of the parts for operating said thread-cutter.

5. A sewing machine having, in combination, stitch-forming mechanism, amain-shaft, a stop-motion device including a stop-cam and gear connectedto the main-shaft to run at a reduced speed and a resilient bufferbetween said stop-cam and gear to absorb the niornentum of the machineparts and impart a reverse motion thereto before bringing the machine toa iinal position of rest, a. needlethread cutter erossing the path ofthe needle, and means actuated by said buffer-spring in the reversemotion of the parts for operating said thread-cutter.

(3. A sewing machine having a frame including a bed, an upright standardand overhanging bracket-arm, stitch-forming mechanism, a work-clamp, a.main-shaft disposed within said bracket-arm and connected to operatesaid stitch-forming mechanism and work-clamp, a stop-motion deviceapplied to the rearward end of the main-shaft and including tight andloose pulleys, a belt-shipper, a stop-cam, a stop-plunger and butlermeans between the stop-cam and the mainsha'i't operating to absorb themomentum of the machine and impart a reverse motion to the parts inbringing the machine to a final position et rest, a rock-shaft mountedexternally ot and alongside said standard, means auxiliary to the sewingoperation connected to be operated by said rock-shaft, and meanscontrolled by the operation et said stop-motion device for actuatingsaid rockshait by the reverse motion of the parts following thebutter-compressing motion.

7. ln a sewing machine, stitch-forming mechanism., a stop-motion device:for controlling its period of operation, said stop-motion devicehaving` a stop-cam, a tilting stop-niotion lever having ruiming andstopping positions, a stop-plunger carried by said lever for cooperationwith said stop-cam, a buil'erspring for absorbing the momentum of themachine and imparting a retrograde motion to the parts in bringing themachine to a final position of rest, a shouldered element running withthe main-shaft, a roclesliaft, an element connected to said rock-shaftand adapted to be operated by said shouldered element in the retrogrademotion of the mainshaft following the buffer-compressing motion, meanson the tilting stop-motion lever for holding said last mentioned elementout of range of said shouldered element while the stop-motion leveroccupies running position, and means auxiliary to the sewing operationconnected to be operated by said rock-shaft after the sewing operationis completed.

8. An automatic sewing machine having, in combination, stitch-formingmechanism, a work-clamp, a stop-motion device for bringing thestitch-forming mechanism to rest at a predetermined position in astitch-forming cycle, said stop-motion device including coactingstop-elements and buffer-means for absorbing the momentum of the machineparts, said buffer means operating to impart a reverse motion to themachine parts following its momentum absorbing action, afol1ower-element adapted to be actuated by one of said machine partsduring the reverse motion, means connected to the stop-motion device forholding said follower-element out of engagement with its actuator duringthe sewing operation, and means operated by said follower-element forperforming a desired operation subsequent to the sewing operation.

9. A sewing machine having stitch-forming mechanism, a main-shaft, astop-motion device having a tilting stop-motion lever, a stop-camrunning with said main-shaft, a stop-plunger carried by said stop-motionlever, a buffer-spring interposed between said stop-cam and main-shaft,whereby the mainshaft has a buffer-compressing motion followed by areverse motion, a rock-shaft and connections for performing a desiredoperation subsequent to the sewing operation, a rock-shaft actuatorrunning with the mainshaft, a follower connected to said rockshaft andadapted to engage said actuator, and means mounted on said stop-motionlever and formed with a cam-portion for controlling the motion of saidfollower into and out of engagement with said actuator, said actuatorcomprising an element having a shoulder arranged to move said followeronly durn ing the reverse motion of the main-shaft following thebu'er-compressing motion.

In testimony whereof I have signed my name to this specification.

EDWARD B. ALLEN.

